hopefully this will run through the file in quick time and then once found the rest of the code will down load the remaining data.
The Stream::findUntil() method still needs to read one byte at a time. It just does it for you. But, that doesn't make it any faster.
In my project I have logged data written to the SD card in .csv format which I can then down load to the PC via the ethernet, however I dont always want the whole file (a years worth is 52,000+ lines).
Having created separate files for each day/week/month might have been smarter.
so 'end of file' is more appropriate but what character is that?
What character did you write as the end-of-file marker? There is no specific end-of-file character.
I'm not sure that you are going about this right. Reading one gigantic string until the data for some specific day is found isn't the way to do it. Read each record. If it's earlier than the requested date, send it out. Read the next.
If the date is not in the range desired, and is after the end date, stop reading.
Of course, this assumes that the records have time/date information, and are in increasing order by date.